301 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



Mopalia ciliata. 



Chcetopleura muscosa Gould, Otia, p. 242, 1862. 



Mopalia muscosa Carpenter, Suppl. Rep. Br. As. 18G3, p. 648. 



Chiton Wossnessenslcii Midd. Mai. Ross, i, p. 101, 1847 ; in part only; figure and 



part of diagnosis excl. 

 Chiton armatus (Nutt. ) Jay, Cat. 1839, No. 2378. No descr. 

 Chiton ornatus Nuttall, MS. Brit. Mus. Col. etc. and 

 Chiton consimilis Nuttall, MS. loc. cit. never described. 



Subsj). Mopalia lignosa. 



Chiton lignosus Gould, Proc. Boston Soc. Nat. Hist, ii, p. 142, July, 1846 ; Otia, p. 



3, 1862 ; Exp. Sh. p. 330, f. 424, 1852. 

 Chcetopleura lignosa Gould, Otia, p. 248, 1862. 

 Mopalia lignosa Carpenter, Suppl. Rep. Br. As. 1863, p. 648. 

 Chiton MercHi Midd. Bull. Imp. Acad. Sci. St. Petersb. t. vi, p. 20, 1846 ; Mai. 



Ross, i, p. 115, pi. xi, f. 5-6, 1847. 

 Chiton Eschsclioltzii Midd. Bull. 1. c. p. 118 ; Mai. Ross. 1. c. p. 114, pi. xi, f. 4 (t. 



jun.). 



Chiton (Hamachiton, Stenosemus) Merclcii Midd. 1. c. p. 34. 

 Chiton Montereyensis Cpr. P. Z. S. 1855, p. 231. 



Chiton vespertinus Gould, Moll. U. S. Expl. Exp. p. 323, f. 426, 426 a, 1852. 



Chwtopleura vesperiina Gould, Otia, pp. 230, 242, 1862. 



Mopalia vespertina H. & A. Adams, Gen. Rec. Moll, i, p. 479, 1854. 



Mopalia Simpsoni Gray, P. Z. S. 1847, p. 69. — H. & A. Adams, Gen. Rec. Moll, i, p. 



479, 1854; Brit. Mus. Coll. In all cases name only; never described. 



(From type.) 



Chiton californicus (Nutt. MS.) Reeve, Conch. Ic. Mon. Chiton, pi. xvi, f. 89, 1847. 

 Var. M. Hindsii. 



Chiton Hindsii (Sowerby MS.) Reeve, Conch. Icon. Mon. Chiton, pi. xii, f. 67, a, 



h, 1847. 



Mopalia Hindsii Gray, P. Z. S. 1847, pp. 69, 169.— H. & A. Adams, Gen. Rec. Moll. 



i, p. 478, pi. liv, f. 7, 1854.— Cpr. Suppl. Rep. Br. As. 1863, p. 213. 



M. t. intus, v. postica ad caudam sinuata; v. centr. unifiss., v. ant. 

 octofissata; dent, longis, suffultis, ssepe extus rugosis; subgrandis mini- 

 mis spongiosis; sinn minimo, acuto, lam. sutur. ab apice antico solum 

 separatism zona setifera seu lanuginosa; valvis parum postice, autice 

 valde apicata ; zona postice hand seu varius hssata. 



Lon. 25-GO, Lat. 15-40 mm. Div. 14(P. 



Hab. — Shumagin Islands (rare) to California; Dall! between tide-marks 

 and at lowest water. Many specimens (hundreds) examined. 



Typical form: sculpture variable, but strong; girdle thickly set with 

 tubular hairs, varying from long, strong bristles to fine, soft pila3. The 

 best distinguishing features are brown or blackish olive color outside; 

 inside, bluish green and lilac; jugular and caudal sinuses narrow, the 

 « latter often not visible externally. 



Snbsp. lignosa : sculpture faint j inside greenish; sinus variable; hairs 

 of the girdle variable, but always softer and shorter than in well-marked 

 ciliata, often hardly perceptible in dry specimens; external colors gray- 

 ish or greenish, with streaks and flammules of brown and white. 



Var. Hindsii: exterior uniform, smoothish; sculpture evanescent; color 

 outside, light olive to nearly black; inside, whitish, carmine in the mo- 



